New York City taxi drivers will soon not just be taking passengers around the city, they're being asked to help spot potential sex trafficking victims.

Under a new city law, drivers should be on the lookout for clues that a passenger is a victim of sex trafficking activity.

In a little under three months the law will kick into effect, and drivers will be required to alert authorities if they see suspicious situations in their cabs which may cause them to believe there is a trafficking victim in the backseat.

The city plans to run a training course for the drivers of taxis and private cars for hire. A video is planned to teach what to look for.

New York cabbies say they understand the value of the sex trafficking law but questioned enforcement. Driver Michael Dick said: "I don't know understand how they're going to enforce it. They don't even enforce the honking law which is a lot easier."

There are few recorded incidents of sex trafficking involving New York cabs but Dorchen Leidholdt, of Sanctuary for Families, an anti-sex trafficking group, says the use of drivers is increasing in the trafficking industry.

Leidholdt said it's a big problem around the world. "We're seeing drivers as an integral part of the sex trafficking industry," she said.

She added: "Sex trafficking is a huge problem in New York, and FBI has identified New York City as a major destination of trafficking victims, but the victims aren't only arriving at our airports, they're also in our inner cities, in our rural areas. We're learning more and more that the vast majority of sex trafficking victims are girls and young women, and sometimes boys, who are born here, who fall under the control of pimps…

"Our trafficking victim clients are telling us over and over again, "I was under a control of a trafficker, but my trafficker was working closely with a driver, who was taking me from buyer to buyer, or picking me up from the street, when I was vulnerable and taking me to a brothel." So, they're working very close together. It's a big problem, actually not only here in New York city and around New York state, but around the world. We're seeing drivers as an integral part of a sex trafficking industry.

"We're hoping that they're gonna become an important arm of law enforcement, because they're in a key position to identify trafficking at the very beginning. But the chief responsibility is you cannot serve as a pimp, you cannot deliberately profit from the commercial sex, sexual exploitation of another human being. That is a crime, you're gonna be held accountable, you're gonna lose your license, you are going to face felony level charges."

Advocacy groups for victims report in some places 'brothels on wheels' are created as drivers are employed to avoid increasing police raids on home where victims are kept.

Opponents said the law unfairly targets cab drivers. One taxi driver accused the backers of practicing 'sexual McCarthyism"

But supporters of the measure also made sure the new law did not include language that would target sex workers or leave room for drivers to question women dressed in a risque manner who are believed to appear involved in illegal sexual activity

A driver convicted of sexual trafficking will lose his license and face a $10,000 fine.